Magnetic switch



Aug. 24, 1954 H. E. COBB in AL 2,687,458

MAGNETIC SWITCH Filed Jul 19, 1950 2 Sheets-Sheet 1 Aug. 24, 1954 H. E. COBB ET AL MAGNETIC SWITCH 2 Sheets-Sheet 2 Filed July 19, 1950 INVENTORS 60% BY Patented Aug. 24, 1954 UNITED STATES PATENT OFFICE 2,687,458 MAGNETIC SWITCH Harold E. Cobb,

Batavia Township, K to Furnas Electric Aurora, and

ane County, Ill.,

corporation of Illinois Application July 19, 1950, Serial No.

William C. Furnas,

assignors 1 Claim. (Cl. 200104) electro-magnet structure trol switches.

The primary object of the present invention is to provide an struction, flexible 1n adaptation,

liable and efiicient in operation.

In our prior copending application Serial No.

155,651, filed April 13,

verted U-shape having an annular energizing coil confined therein, and a reciprocable laminated armature of inverted T-shape having a cross-bar Another important object of provide an other damaging influences.

Still another object of our invention is to pro- An additionalobject of the present invention is to provide various improvements in electromagnet structures, whereby the field and armature 55 These and other objects and advantages of the invention will be readily apparent from the following description.

A clear conception of the several features which constitute our present improvement, and of the devices associated therewith;

Fig. 2 is a bottom view of the magnetic switch unit showing the same confined within its housing casing and cover both shown in section;

Fig. 3 is a main switch contacts open;

Fig. 4 is a top view of the movable contact actuating magnet with the switch contacts and carrier omitted;

herein be given tation consistent Referring to the drawings, the typical improved magnetically actuated switch unit shown therein, comprises in general, a main switch housing or casing in having a front closure cover ll; a mounting frame or plate l2 detachably secured to the rear wall of the casing is by upper and lower screws l3, M respectively, and having thereon a pair of partial punchings l5; a magnetic field piece consisting of a U-shaped lower section It rigidly attached as by welding to the plate punchings l5 and being spanned by an upper plate section ll having a hollow laminated stop core is depending from its medial portion; an annular magnet energizing coil l9 confined within the field section It and surrounding the core 18; a laminated armature plunger 20 reciprocable within the coil 19 in alinment with the core l3 and slidably cooperating with a lower guide block 21, the plunger 28 having a central pusher rod 22 passing through and guided within the core 18; a contactcarrying and housing board 23 mounted above the plate section ll of the field piece and providing a support for front and rear fixed contacts 24, 25; and movable contacts 26,. 21 resiliently supported upon the upper end of the push rod 22 and being cooperable with the fixed contacts 24, 25 to make and break electric circuits.

The casing l0 and cover H may be lined with insulation and formed of sheet metal, and the cover is detachably secured to the casing ID by means of lugs 29 formed on this casing and coacting with slots in the cover I l, and by a-screw 3i} coacting with the lower overlapped portions of the casing and cover, see Figs. 1 and 3. The switch mounting frame plate 12 may also be formed of durable sheet metal and is provided with slots 31 at its upper side portions which are adapted to cooperate with the upper screws H as shown in Fig. l, and this plate l2 also has a pair of thermal overload relays 32 secured thereto on the opposite sides of the magnetic structure by means of screws 33 shown in Fig. 2, and is normally detachably secured within the casing it by the single lower screw [4. Each of the overload relays 32 is provided with a reset plunger slide 35 normally concealed within the casing in but adapted to project through an adjacent lower casing opening as illustrated in dot-and-dash lines in Fig. 1 when the relay has sprung into circuit interrupting position; and the casing is also provided with suitable terminal outlets in a well known manner and has suspension holes or slots 35 formed in its rear wall.

The two sections It, ll of the field piece are formed of heavy magnetic sheet metal and have tongue and groove connections 3'! at the opposite sides thereof as shown in Fig. 4, and the front portions of these sections l6, H are clamped together by upwardly directed long screws 38 which also clamp the block 2| to the lower U-section 16, while the rear portions of the sections Ni, ii are clamped together by downwardly directed long screws 39 which also firmly clamp the terminal board 23 to the upper plate section ll. The guide block 2i which is formed of insulation, is additionally clamped to the bottom of the U-section it by a single central rear short screw 40, and all of these screws 38, 39, 40 clear the annular coil IS which is snugly confined within the lower U-section it by the upper plate section H. The laminated upper stop core it may be swaged and welded to the top plate section ii and is provided with shading coils il embedded in its lower face, and the laminations of this core 18 are formed of magnetic material and are bound together by transverse straps 22 as clearly shown in Figs. 3 and 6.

The laminations of the reciprocable armature plunger 29 are also formed of magnetic metal and are bound together by transverse straps M, and this plunger 22 is freely movable through a central opening in the bottom of the U-section IE but is snugly slidable within the lower guide block 25. The plunger rod 22 is formed of non-magnetic bar stock such as stainless steel, and is likewise snugly slidable within the bore of the hollow core is, so that the vertically movable plunger l8 cannot shift laterally. An L-shaped bracket 45 which is also formed of non-magnetic sheet metal is firmly welded or otherwise secured to the upwardly protruding end of the plunger rod 22, and a movable contact carrying cross beam 46 is by means of eral sets of movable contacts 26, .2-1 are secured to horizontal plates d8 formed of conducting material which are slidably and tiltably but detachably mounted upon contact guides 49 firmly secured to the cross beam 46, and which are resiliently urged toward the adjacent sets of fixed contacts 2 25 by helical compression springs 50.

The fixed contact carrying board 23 which is firmly secured to the pole piece sections l6, l-l by the rear screws 39, is also formed of insulating material and is shaped to normally conceal the fixed and movable contacts 24, 2'5, 25, 2'1.

The adjacent sets of these fixed and movable contacts are segregated from each other by partitions 52 formed integral with and the front contacts 24 are secured to lower conductor bars 53 attached to the board 23 by screws 5s and which terminate in terminal screws 55, while the rear contacts 26 are secured to polygonal mounting elements 56 fastened to upper conductor bars 5"! attached to the board 23 by other screws 58, and which terminate in terminal screws 59, see Figs. 1, 3 and .5. The polygonal elements '56 are attached to the corresponding .conductor bars 51 by screws Gil, and coact allel sided recesses prevent possible rotation of the contacts 25 carried thereby. The front portion of board 23 is also provided with an integral horizontal flange 5! which segregates the terminal screws 55, 59 from each other, thus effectively protecting the contacts and terminals against possible short circuiting.

in order to complete the magnetic controller unit, an auxiliary start and stop push button switch 6t may also be mounted within the casing it upon the front leg or wall of the field piece section it, and this switch 53 is preferably attached to an insulating board or plate ii'l by screws 65 while the plate 64 is firmly but detacha'bly secured to the guide block H by screws 66 and has its upper end engaged by the contact board 23, see Figs. 1, 2 and 3. The auxiliary switch 63 is provided with an upper starting button B1 and with a lower stopping button 88 both of which are readily accessible through an opening G?) in the casing cover ll, and this push but-r.

ton switch assembly may be replaced by any other suitable type of start andstop switch. By mounting the switch 83 and the contact carrying board 23 upon elements may be rigidly suspended from the frame plate i2, and by also mounting the overload relays 32 upon the plate 12 the entire switch assemblage the board 2-3;

with par formed in the board 23 so as,

the terminal the magnet pole piece, these long screws 38,

y be applied or removed as a unit within the main casing'..|0,. v "While all of the diagram, =currentuis supplied to the system lines the magnet energizing coil l9 may be applied to the circuit as show In order to start the electric motor 12 it is merely necessary to press the starting button 67 of the auxiliary switch 63, whereupon the magnet coil I9 will be energized and will cause the laminated fixed core [8 to atable contacts 26, 2! into engagement with the adjacent fixed contacts 24, 25 as illustrated in Fig. 5, and causing the motor 12 to operate normally.

If, however, the current rises abnormally, then the thermal overload relays 32 will promptly function to break the circuit and the slides 34 of these relays will be projected outwardly of the casing i I as illustrated in dot-and-dash lines in Figs.

as to when the overload relays 32 have functioned.

and resultant noise;- and the movable contacts 26, 21 are flexibly and resiliently mounted upon the transverse carrier beam 46 thereby insuring efiective closing of all contacts. Both the fixed and the movable contacts are confined within and amply protected against insulated terminal board 23, and the auxiliary screws [3, The improved magnetic switch unit has proven highly satisfactory in actual use and may be produced at moderate cost for diverse uses.

While the thermal overload relays may be replaced by other types adapted to function in a similar manner.

the art.

We claim:

In a magnetic switch, a U-shaped field-piece of magnetic metal provided with upright parallel cross-section than said bottom plate opening disposed in vertical alinement with said bottom plate opening, a laminated plunger of magnetic core bore and projecting upwardly beyond said top plate, a switch contact mounting board of insulation enacting with the upper .iace or said top :plate Number Name Date andhavingfixedcontacts mountedthereimmov- Re. 20,676 Wilms et a1. Mar.22, v1938 able-switch contacts carriedaby thenpper end of 8039186 .Hill 7.. Oct. 31, 1905 said .plungermodand being cooperableuwith .said 926,661 I Ryan June 29, .1909 fixedcontacts, means closely adjacent tonne of 5 1,019,045 :Hor'ton M81125, 1912 said wallsior .detachably clampingsaidtopaplate 1,201,491 Neahr Oct..1'l, 1916 andrsaid guide block againstsaid fie1d-piece,'and 1.893.827 Getchell Jan. 10, 1933 means.c1ose1yadjacent'vto the other of said walls 2,013,013 Van Valkenburg Septr3, 1935 for detachablyvclamping said guideblock'andrsaid 2278967 Allen Apr. "7, 1942 mounting :board to'said field-piece and said top 10 .-2;304',972 Van Valkenburget 91. Dec. 15,1942 plate respectively. 6 7 2,352,550 Joseph 'June27, 1944 V v 2,391,277 Stapleton Dec. '18, 1945 References Cited in the file 'Of this patent 2,401,963 Persons Sept, 1'], 1946 UNITEDJSTATES'PATENTS 2,421,290 Schleicher May 27, 194'! 15 2,472,553 Theunissen June "1, 1949 Number Name Date 7 V 86.201094 .W et a1. "Sept 1,1936 2,505,904 Matthia etal. May 2. 1950 

